JP2015077551A - Phosphorus removal type wastewater treatment process and phosphorus removal type wastewater treatment system - Google Patents

Abstract

To remove phosphorus from organic waste water. A phosphorus removal wastewater treatment system according to an embodiment includes an anaerobic treatment unit, an aerobic treatment unit, and a phosphorus treatment unit. The aerobic treatment part includes a carrier part to which aerobic microorganisms are attached and a watering part for sprinkling treated water from the anaerobic treatment part to the carrier part. The phosphorus adsorbent includes a calcium-based phosphorus adsorbing substance, and the phosphorus treatment unit reacts phosphorus in the treated water from the aerobic processing unit with the calcium-based phosphorus adsorbing substance to generate hydroxyapatite crystals. [Selection] Figure 1

Description

  Embodiments described herein relate generally to a phosphorus removal wastewater treatment process and a phosphorus removal wastewater treatment system used therefor.

  Conventionally, as a means for purifying organic wastewater, many wastewater treatment apparatuses comprising a combination of an anaerobic reactor using an anaerobic microorganism and an aerobic reactor using an aerobic microorganism have been proposed.

  Treatment methods using anaerobic microorganisms include anaerobic filter bed method, UASB method (Upflow Anaerobic Sludge Blanket), EGSB method (Expand Granular Sludge bed method). is there. These anaerobic treatments have the following advantages.

(1) Since water treatment is performed with anaerobic microorganisms that do not require oxygen when decomposing organic pollutants, treatment can be performed at a lower cost than a treatment method using aerobic microorganisms. (2) Aerobic microorganisms are organic matter. About 0.4-0.6g per 1g removal, while anaerobic microorganisms grow about 0.1g per 1g organic matter removal, the amount of sludge generated per organic matter removal can be significantly reduced. However, as a disadvantage, it is difficult to process BOD to a level of 10-15 (mg / L) or less only by anaerobic processing, and it is preferable for subsequent processing in processing facilities that discharge directly into rivers and lakes. It is common to install a gas reactor.

  Examples of treatment methods using aerobic microorganisms include activated sludge method, aerobic filter method, sprinkling filter method, and rotating disc method. The aerobic treatment can be classified into an immersion type and a non-immersion type. The immersion type treatment method is a process in which aerobic microorganisms are always immersed in water, and the activated sludge method and the aerobic filter bed method correspond to this. In these processes, oxygen used by aerobic microorganisms must be supplied by aeration treatment (air or pure oxygen is blown into the water), but the power cost for this aeration treatment accounts for the majority of the cost of the water treatment process. Occupy.

  On the other hand, the non-immersion type treatment method is not a method in which aerobic microorganisms are always immersed in water, but is a method in which air in the atmosphere is dissolved in the liquid by taking a large gas-liquid contact surface, Since the aeration process is unnecessary, the power cost can be kept low.

  As a process that can greatly reduce the power cost for water treatment, for example, a water treatment method in which an anaerobic reactor and a non-immersion type aerobic reactor (watering type aerobic reactor) are combined has been proposed. However, in a water treatment system that combines an anaerobic reactor and a non-immersed aerobic reactor (watering type aerobic reactor), phosphorus in organic wastewater cannot be removed.

  In closed waters of inner bays such as Tokyo Bay and lakes such as Lake Biwa, problems of eutrophication due to phosphorus have become apparent, and removal of phosphorus from wastewater is required. On the other hand, phosphorus is an important resource especially as a fertilizer for agricultural crops. However, Japan does not produce phosphorus ore and relies on 100% import, and it is difficult to recover and recycle phosphorus from wastewater. This is a demanded situation.

  As a technique for recovering phosphorus from wastewater, there is a method using a phosphorus adsorbent. However, when applied to sewage treated water, the phosphorus concentration in the sewage treated water is low, so when the used phosphorus adsorbent is reused as fertilizer, the adsorbent has a small amount of phosphorus adsorbed and reused as fertilizer. It has become difficult to do.

JP 2010-274206 A

  Embodiments of the present invention provide a phosphorus removal wastewater treatment system that enables phosphorus removal from organic wastewater, and further allows the phosphorus adsorbent used for phosphorus removal to be reused as a fertilizer, and a phosphorus removal wastewater using the same. The purpose is to provide a processing process.

According to the embodiment, an anaerobic treatment unit that treats organic wastewater using anaerobic microorganisms,
A carrier part to which aerobic microorganisms are attached, and a watering part for sprinkling treated water from the anaerobic treatment part to the carrier part, wherein the treated water from the anaerobic treatment part is treated with the aerobic microorganism. And a first phosphorus adsorbent containing a calcium-based phosphorus adsorbing substance, and reacting phosphorus in the treated water from the aerobic processing section with the calcium-based phosphorus adsorbing substance to form hydroxyapatite crystals. There is provided a phosphorus removal wastewater treatment system including a first phosphorus treatment section to be generated.

It is a figure showing the structure of the waste water treatment system which concerns on 1st Embodiment. It is a figure showing the structure of the waste water treatment system which concerns on 2nd Embodiment. It is a figure showing the structure of the waste water treatment system which concerns on 3rd Embodiment. It is a figure showing the structure of the waste water treatment system which concerns on 4th Embodiment. It is a figure showing the structure of the waste water treatment system which concerns on 5th Embodiment. It is a figure showing the structure of the waste water treatment system which concerns on 6th Embodiment. It is a figure showing the structure of the waste water treatment system which concerns on 7th Embodiment.

The phosphorus removal wastewater treatment system according to the embodiment is
An anaerobic treatment section for treating organic wastewater using anaerobic microorganisms,
An aerobic treatment unit that treats treated water from the anaerobic treatment unit using an aerobic microorganism, and a first phosphorus treatment that has a first phosphorus adsorbent and removes phosphorus in the treated water from the aerobic treatment unit Part.

  The aerobic treatment part includes a carrier part to which aerobic microorganisms are attached and a watering part for sprinkling treated water from the anaerobic treatment part to the carrier part.

  The phosphorus adsorbent used in the embodiment includes a calcium-based phosphorus adsorbent, and the first phosphorus treatment unit reacts phosphorus in the treated water from the aerobic treatment unit with the calcium-based phosphorus adsorbent to produce hydroxyapatite crystals. It is possible to remove phosphorus from the treated water.

Moreover, the phosphorus removal type wastewater treatment process according to the embodiment is
A process of introducing organic wastewater into the anaerobic treatment section and anaerobic treatment using anaerobic microorganisms,
The aerobic microorganisms are introduced into the aerobic treatment part including the carrier part to which the aerobic microorganisms are attached and the watering part for spraying the treated water from the anaerobic treatment part to the carrier part. Aerobic treatment using the process, and the treated water from the aerobic treatment part is introduced into the first phosphorus treatment part having the first phosphorus adsorbent containing the calcium phosphorus adsorption substance, A step of reacting phosphorus in the treated water from the temper treatment section to produce hydroxyapatite crystals.

  According to the embodiment, since the carrier portion is aerated by sprinkling the treated water on the carrier portion to which the aerobic microorganisms are attached, the power cost for aeration can be reduced. In addition, by having a phosphorus adsorbent containing a calcium-based phosphorus adsorbing material, by reacting phosphorus in the treated water from the aerobic processing unit and calcium-based phosphorus adsorbing material to generate hydroxyapatite (HAP) crystals, The phosphorus adsorption agent after a process can be used as a fertilizer as it is.

  The calcium-based phosphorus-adsorbing material can be used in combination with the magnesium-based phosphorus-adsorbing material. By using the calcium-based phosphorus adsorbing material and the magnesium-based phosphorus adsorbing material, the phosphorous treatment unit can bring the treated water from the aerobic treatment unit into contact with the calcium-based phosphorus adsorbing material and the magnesium-based phosphorus adsorbing material. It is possible to produce HAP crystals by reacting with phosphorous, and to produce magnesium ammonium phosphate (MAP) crystals by reacting with phosphorus and ammonia in the treated water.

  As a method of recovering phosphorus, there are a method of crystallizing phosphorus in the treatment liquid as hydroxyapatite (HAP) and a method of crystallizing as struvite (MAP) as described above.

In the method of crystallization as HAP, the crystallization phenomenon of HAP; Ca ₁₀ (OH) ₂ (PO ₆ ) (HAP) generated by reaction with PO ₄ ³⁻ , Ca ²⁺ and OH ⁻ in the treatment liquid is used. . The reaction formula is as shown in the following formula (1).

10Ca ²⁺ + 2OH ⁻ + 6PO ₄ ³⁻ ⇔Ca ₁₀ (OH) ₂ (PO ₄ ) ₆ (1)
In this method, Ca ²⁺ and OH ⁻ are added to waste water containing phosphorus and brought into contact with the seed crystal in a supersaturated state (metastable region), so that HAP is crystallized on the surface of the seed crystal, and phosphorus in the treatment liquid is removed. Remove and collect. When the phosphorus concentration is low, a competitive reaction with calcium carbonate occurs, so that treatment such as decarboxylation may be necessary. As the seed crystal, phosphate rock, bone charcoal, calcium silicate hydrate and the like can be used.

In the method of crystallization as MAP, the crystallization phenomenon of magnesium ammonium phosphate produced by the reaction of PO ₄ ³⁻ , NH ₄ ⁺ , and Mg ^{2+ in} the treatment liquid; MgNH ₄ PO ₄ .6H ₂ O (MAP) Use. The reaction formula is as follows.

Mg ²⁺ + NH ₄ ⁺ + PO ₄ ^{3 −} + 6H ₂ O⇔MgNH ₄ PO ₄ .6H ₂ O (2)
In this method, wastewater containing phosphorus and ammonia is targeted. As an example, Mg ²⁺ can be added to the treated water of the anaerobic treatment unit to generate MAP in the weak alkali region.

  Hereinafter, embodiments will be described with reference to the drawings.

(Example 1)
In FIG. 1, the figure showing the structure of the waste water treatment system which concerns on 1st Embodiment is shown.

  In the wastewater treatment system 101 according to the first embodiment, the water feeding device 2 supplies the organic wastewater in the line 1 to the bottom of the anaerobic treatment tank 3.

  The anaerobic treatment tank 3 has anaerobic microorganisms such as methane fermentation bacteria and sulfate-reducing bacteria. The organic matter in the organic waste water 1 is decomposed in the anaerobic treatment tank 3 by methane fermentation bacteria and sulfate-reducing bacteria, and at the same time, methane gas and hydrogen sulfide gas are generated. These biogas 4 are sent to a hydrogen sulfide removing device 5 provided above the anaerobic treatment tank 3 to remove the hydrogen sulfide gas, and then discharged from the hydrogen sulfide removing device 5 as a processing gas 6 containing methane gas as a main component. To do.

  Next, the anaerobic treated water treated in the anaerobic treatment tank 3 is introduced into the aerobic treatment tank 8 through the line 7. The aerobic treatment tank 8 is provided with, in order from the top, a watering part 9, a carrier part 10 to which aerobic microorganisms are attached, and a sludge precipitation part 11 for precipitating the treated sludge.

  When anaerobic treated water is sprinkled from the upper sprinkling section 9, oxygen in the atmosphere is dissolved in the treated water during this sprinkling. The aerobic treatment tank 8 is filled with the carrier 10, and until it reaches the sludge settling part 11 at the lower part of the aerobic treatment tank 8, the gap between the carriers 10 is always sewed and the water has fallen. is there. Oxygen is supplied into the treated water by gas-liquid contact between the air and the liquid during watering and while the water sews and falls between the carriers 10. The aerobic microorganisms adhering to the carrier 10 decompose and remove organic matter that could not be treated in the anaerobic treatment tank 3 while utilizing oxygen dissolved in the liquid (hereinafter, dissolved oxygen). Depending on the level of the concentration of organic matter flowing into the aerobic treatment tank 8, a sufficient amount of oxygen is supplied at the natural air convection level, but if necessary, air is forced into the aerobic treatment tank by a ventilation fan. Can be configured to insufflate.

  The carrier 10 filled in the aerobic treatment tank may be anything as long as microorganisms are easily attached to the surface. For example, any material such as plastics mainly made of polypropylene, polyethylene, ceramics, metals, etc. Can be used. As the shape of the carrier 10, for example, a spherical shape, a cylindrical shape, a string shape, and a honeycomb shape can be used. The size of the carrier 10 is, for example, about 1 cm to 5 cm in length, and one having a large specific surface area can be used.

  When applying the so-called standard activated sludge method, which is the mainstream in sewage treatment plants, to the wastewater treatment, a decarboxylation tower is installed to remove interfering ions (carbonate ions) in the aerobic treated water. It is necessary and the cost increases accordingly. However, as shown in FIG. 1, in the case of a water treatment method in which an anaerobic treatment tank and a non-immersed aerobic treatment tank (watering type aerobic reactor) are combined, the anaerobic treated water 7 is placed on the upper part of the aerobic treatment tank 8. When water is sprinkled from the water sprinkling section, carbonate ions are diffused from the anaerobic treated water 7, so that phosphorus can be removed without providing a decarbonation tower.

  Subsequently, the aerobic treated water treated in the aerobic treatment tank 4 is introduced into the first phosphorus treatment tank 15 through the line 12.

  In the first phosphorus treatment tank 15, phosphorus can be recovered as HAP crystals by injecting a calcium salt such as calcium silicate hydrate. After the phosphorus is removed, the phosphorus-treated water 16 can be discharged from the first phosphorus treatment tank 15.

  The phosphorus-treated water treated in the first phosphorus treatment tank 15 is introduced into the treated water storage tank 13 through the line 16 and stored, and then discharged as final treated water 14 into a river or the like.

  Thus, according to the first embodiment, in the water treatment system in which the anaerobic treatment tank and the non-immersion type aerobic treatment tank (sprinkling type aerobic treatment tank) are combined, the latter stage of the sprinkling type aerobic treatment tank. It is possible to remove phosphorus from the organic waste water by arranging the first phosphorus treatment tank by HAP crystal precipitation.

(Example 2)
In FIG. 2, the figure showing the structure of the waste water treatment system which concerns on 2nd Embodiment is shown.

  As shown in the figure, the waste water treatment system 102 according to the second embodiment is different from that shown in FIG. 1 except that it further includes a sedimentation tank 17 provided between the first phosphorus treatment tank 15 and the treated water storage tank 13. It has the same configuration as. In the sedimentation tank 17, the treated water from the phosphorus treatment tank 15 is introduced and stored through the line 16, and HAP crystals are precipitated as a solid content.

  Since the HAP crystals precipitated in the phosphorus treatment tank 15 may partially flow out and be contained in the phosphorus treatment water, the precipitation tank 17 precipitates the HAP crystals in the phosphorus treatment water that has flowed out of the phosphorus treatment tank 15 as a solid content. Then, the precipitated treated water is introduced into the treated water storage tank 13 via the line 18 and stored, and then discharged as a final treated water 14 to a river or the like.

  According to Example 2, in a water treatment system in which an anaerobic treatment tank and a non-immersion type aerobic treatment tank (a sprinkling type aerobic treatment tank) are combined, phosphorous by HAP crystal precipitation is provided downstream of the sprinkling type aerobic treatment tank. By disposing the sedimentation tank downstream of the treatment tank and the phosphorus treatment tank, it becomes possible to remove more phosphorus from the organic waste water.

(Example 3)
In the first phosphorus treatment tank 15, instead of injecting the calcium salt of Example 1, by introducing a Ca-based adsorbent, HAP crystals are precipitated on the Ca-based adsorbent and phosphorus is recovered as HAP crystals. Except for this, organic wastewater was treated in the same manner as in Example 1.

  Thus, according to Example 3, in the water treatment method in which the anaerobic treatment tank and the non-immersion type aerobic treatment tank (sprinkling type aerobic treatment tank) are combined, the HAP is disposed downstream of the sprinkling type aerobic treatment tank. By arranging the first phosphorus treatment tank by crystal precipitation, it is possible to remove phosphorus from the organic wastewater even if a Ca-based adsorbent is added instead of injecting calcium salt into the first phosphorus treatment tank. Is possible.

Example 4
In the first phosphorus treatment tank 15, instead of injecting the calcium salt of Example 1, the Ca-based / Mg-based adsorbent is charged with the HAP crystal and the MAP crystal. The organic waste water was treated in the same manner as in Example 1 except that phosphorus was recovered and phosphorus could be recovered as HAP / MAP crystals.

  Thus, according to Example 4, in the water treatment method in which the anaerobic treatment tank and the non-immersion type aerobic treatment tank (sprinkling type aerobic treatment tank) are combined, the HAP is disposed downstream of the sprinkling type aerobic treatment tank. By arranging the first phosphorus treatment tank by crystal precipitation, instead of injecting calcium salt into the first phosphorus treatment tank, even if Ca-based / Mg-based adsorbent is added, phosphorus is removed from the organic waste water. It can be removed.

(Example 5)
In the first phosphorus treatment tank 15, instead of injecting the calcium salt, a Ca-based adsorbent or a Ca-based / Mg-based adsorbent is added to the Ca-based adsorbent, so that HAP crystals or Ca-based / Mg-based materials The organic waste water was treated in the same manner as in Example 2 except that HAP crystals and MAP crystals were precipitated on the adsorbent and phosphorus was recovered.

  According to Example 5, in a water treatment system in which an anaerobic treatment tank and a non-immersion type aerobic treatment tank (watering type aerobic treatment tank) are combined, phosphorus by HAP crystal precipitation is provided downstream of the watering type aerobic treatment tank. By disposing a precipitation tank downstream of the treatment tank and the phosphorus treatment tank, even if a Ca-based adsorbent and a Ca-based / Mg-based adsorbent are added, more phosphorus can be removed.

(Example 6)
In FIG. 3, the figure showing the structure of the waste water treatment system which concerns on 3rd Embodiment is shown.

  As shown in the figure, the wastewater treatment system 103 according to the third embodiment anaerobically treats the first sedimentation basin treatment water composed of the first sedimentation basin 19 and the supernatant from the first sedimentation basin 19 at the front stage of the anaerobic treatment tank 3. The sludge from the line 20 to be sent to the tank 3 and the first sedimentation basin 19 is introduced through the line 21, the sludge digestion tank 22 to be anaerobically treated, the treated water from the sludge digestion tank 22 is introduced through the line 23, and the sludge is Sludge dewatering tank 24 for dewatering treatment, line 28 for discharging sludge from sludge dewatering tank 24, and seed crystals of HAP crystals or phosphorus adsorbing substances, and treated water from sludge dewatering tank 24 through line 25 And introducing a second phosphorus treatment unit 26 for reacting phosphorus in the treated water with seed crystals of HAP crystals, or Ca-based adsorbents or Ca-based / Mg-based adsorbents to generate HAP crystals or MAP crystals. Having Has the same configuration as in Example 1. If necessary, a line 27 for sending treated water from the second phosphorus treatment unit 26 to the anaerobic treatment tank 3 can be further provided.

  In the first sedimentation basin 19, the solid content in the organic waste water introduced by the line 1 is settled, and the first sedimentation basin sludge is extracted from the lower part of the first sedimentation basin 19 by the line 21 and supplied to the sludge digestion tank 22. The supernatant water after the solid content in the organic waste water 1 is precipitated in the first sedimentation basin 19 is discharged via the line 20 as the first sedimentation basin treatment water and supplied to the anaerobic treatment tank 3.

  In the sludge digestion tank 22, the first sedimentation basin sludge 21 is decomposed by the anaerobic microorganisms methane fermentation bacteria and sulfate-reducing bacteria, and at the same time, methane gas and hydrogen sulfide gas are generated. The first sedimentation basin sludge 21 after decomposition is discharged as digested sludge 23 and supplied to the sludge dewatering tank 24.

  In the sludge dewatering tank 24, the digested sludge 23 is dehydrated and discharged from the lower part of the sludge dewatering tank 24 through the line 28 as dehydrated sludge. The dehydrated supernatant water is supplied to the second phosphorus treatment tank 26 as a desorbed liquid via the line 25.

  In the first phosphorus treatment tank 15 and the second phosphorus treatment tank 26, for example, by introducing a Ca-based / Mg-based adsorbent, HAP and MAP crystals are precipitated in the Ca-based / Mg-based adsorbent, and the HAP / Phosphorus in the treated water can be recovered as MAP crystals.

  In the first phosphorus treatment tank 15, even if phosphorus is removed from the aerobic treated water sent out by the line 12, the phosphorus concentration in the treated water tends to be low, and the phosphorus adsorbent after the wastewater treatment is reused as fertilizer as it is. It is difficult to use. For this reason, at least a part of the phosphorus adsorbent is recovered from the first phosphorus treatment tank 15 subsequent to the aerobic treatment tank, put into the second phosphorus treatment tank 26, and phosphorus in the desorbed liquid sent out by the line 25. Are further precipitated as HAP crystals and MAP crystals to remove phosphorus in the organic waste water. In this way, by adsorbing a higher concentration of phosphorus to the phosphorus adsorbent, the phosphorus adsorbent can be reused as a fertilizer as it is. In addition, although not shown in the drawings, the supernatant water after the first sedimentation basin sludge 21 decomposition in the sludge digestion tank 22 can be supplied to the phosphorus treatment tank 26 to remove phosphorus.

  According to the third embodiment, in the water treatment method in which the anaerobic treatment tank and the non-immersion type aerobic treatment tank (watering type aerobic treatment tank) are combined, the first settling basin is provided in the front stage of the anaerobic treatment tank. Then, the sludge and the supernatant liquid are separated, and the supernatant liquid can be removed using the first phosphorus treatment tank, and the sludge can be removed using the second phosphorus treatment tank 26, respectively. In addition, at least one part of the HAP crystal itself or the phosphorus-adsorbing material on which the HAP crystal and the MAP crystal are deposited in the first phosphorus treatment tank is moved to the second phosphorus treatment tank, and the HAP in the second phosphorus treatment tank is obtained. It is possible to adsorb a high concentration of phosphorus to the phosphorus adsorbing material by further depositing the HAP crystal and the MAP crystal as a seed crystal or a phosphorus adsorbing material. The adsorbent adsorbed with high concentration of phosphorus can be reused as fertilizer.

(Example 7)
In FIG. 4, the figure showing the structure of the waste water treatment system which concerns on 4th Embodiment is shown.

  As shown in the figure, the wastewater treatment system 104 according to the fourth embodiment is the same as that shown in FIG. 3 except that it further includes a sedimentation tank 17 provided between the first phosphorus treatment tank 15 and the treated water storage tank 13. It has the same configuration as. In the sedimentation tank 17, treated water from the phosphorus treatment tank 15 is introduced and stored through the line 16, and the HAP crystal itself, Ca-based adsorbent, or Ca-based / Mg-based adsorbent is precipitated as a solid content.

  The aerobic treated water treated in the aerobic treatment tank 4 is sent to the first phosphorus treatment tank 15 through the line 12. After removing phosphorus in the first phosphorus treatment tank 15, it passes through the line 16 and is introduced into the precipitation tank 17 as phosphorus treatment water.

  In the first phosphorus treatment tank 15 and the second phosphorus treatment tank 26, for example, by introducing a Ca-based adsorbent or a HAP / MAP crystal, crystals of HAP and MAP are precipitated on the Ca-based / Mg-based adsorbent. And phosphorus can be recovered as HAP / MAP crystals.

  In the phosphorus treatment tank 15, the HAP crystal itself, the Ca-based adsorbent on which HAP crystals are precipitated, or the Ca-based / Mg-based adsorbent on which HAP / MAP crystals are precipitated partially flows out and is mixed in the phosphor-treated water 16. In the precipitation tank 17, the HAP crystal itself, the Ca-based adsorbent, and the Ca-based / Mg-based adsorbent in the phosphorus-treated water 16 flowing out from the phosphorus treatment tank 15 are precipitated as solids, and then precipitated. After being discharged into the treated water storage tank 13 as treated water 18 and stored, it is discharged as a final treated water 14 into a river or the like.

  According to the fourth embodiment, it is possible to remove more phosphorus from the organic wastewater than in Example 6 by arranging the precipitation tank downstream of the phosphorus treatment tank.

(Example 8)
In FIG. 5, the figure showing the structure of the waste water treatment system concerning 5th Embodiment is shown.

  As shown in the drawing, the waste water treatment system 105 according to the fifth embodiment is arranged in a first line 12 and a first line 12 for introducing treated water from the aerobic treatment tank 8 into the first phosphorus treatment tank 15. The first pipe switching valve 29 provided, the second line 41 for sending the treated water from the aerobic treatment tank 8 to the second phosphorus treatment tank 26, and the second pipe provided in the second line 41 A third line 25 for introducing treated water from the switching valve 36 and the sludge dewatering tank 24 into the second phosphorus treatment unit 26, a third pipe switching valve 31 provided in the third line 25, and the sludge dewatering tank 24 3 except that it further has a fourth line 42 for introducing treated water from the first phosphorus treatment tank 15 and a fourth pipe switching valve 30 provided in the fourth line 42. It has a configuration.

  In this waste water treatment system 105, first, an unused phosphorus adsorbent is introduced into the phosphorus treatment tank 15 through a normal water flow line. In a normal water flow line, the first pipe switching valve 29 is opened, the second pipe switching valve 36 is closed, the third pipe switching valve 31 is opened, and the fourth pipe switching valve 30 is closed. Thus, the treated water from the aerobic treatment tank 8 can be introduced into the first phosphorus treatment tank 15 and the treated water from the sludge dewatering tank 24 can be introduced into the second phosphorus treatment tank 26.

  After adsorbing phosphorus in the aerobic treated water 12 for a certain time, the first pipe switching valve 29 is closed, the second pipe switching valve 36 is opened, the third pipe switching valve 31 is closed, and the fourth The water switching system line and the sludge treatment system line are switched by opening the pipe switching valve 30 of this, the treated water from the aerobic treatment tank 8 is introduced into the second phosphorus treatment tank 26, and the sludge dewatering tank The treated water from 24 can be introduced into the first phosphorus treatment tank 15.

  After adsorbing phosphorus in the desorbing liquid 25 for a certain time, the phosphorus adsorbent is recovered from the phosphorus adsorbent tank 15 and used as it is as a fertilizer. After taking out the phosphorus adsorbent from the phosphorus adsorbent tank 15, unused phosphorus adsorbent is put into the phosphorus adsorbent tank 26. Thereafter, this operation is repeated.

  Thus, according to the fifth embodiment, by controlling the opening and closing of the first to fourth pipe switching valves, the water treatment system line and the sludge treatment system line introduced into the two phosphorus treatment tanks, respectively. Can be switched. For this reason, in the water treatment system which combined the anaerobic treatment tank and the non-immersion type aerobic treatment tank (watering type aerobic treatment tank), the Ca-based adsorbent and the Ca-based / Mg-based adsorbent are not recovered. Moreover, since it is not necessary to stop the treatment of organic wastewater and the treatment of sludge such as the first sedimentation basin for this recovery, phosphorus can be adsorbed efficiently.

Example 9
FIG. 6 shows a wastewater treatment system according to the sixth embodiment.

  As shown in the figure, the waste water treatment system 106 according to the sixth embodiment is shown in FIG. 5 except that it further includes a sedimentation tank 17 provided between the first phosphorus treatment tank 15 and the treated water storage tank 13. It has the same configuration as. In the sedimentation tank 17, treated water from the phosphorus treatment tank 15 is introduced and stored through the line 16, and the HAP crystal itself, Ca-based adsorbent, or Ca-based / Mg-based adsorbent is precipitated as a solid content.

  The HAP crystal itself, Ca-based adsorbent, and Ca-based / Mg-based adsorbent precipitated in the phosphorus treatment tank 15 may partially flow out and be contained in the phosphorus-treated water. After the HAP crystals, Ca-based adsorbent, and Ca-based / Mg-based adsorbent in the phosphorus-treated water flowing out from the reactor are precipitated as solids, the precipitated treated water is introduced into the treated water storage tank 13 via the line 18 and stored. After that, the final treated water 14 is discharged into a river or the like.

  According to the sixth embodiment, in a water treatment method in which an anaerobic treatment tank and a non-immersion type aerobic treatment tank (sprinkling type aerobic treatment tank) are combined, HAP crystal precipitation is performed after the sprinkling type aerobic treatment tank. It becomes possible to remove more phosphorus from the organic waste water by arranging the precipitation tank in the downstream of the phosphorus treatment tank and the phosphorus treatment tank.

  Further, according to the sixth embodiment, in the water treatment method in which the anaerobic treatment tank 3 and the non-immersion type aerobic treatment tank 8 (watering type aerobic treatment tank) are combined, It is possible to remove phosphorus without collecting the Mg-based adsorbent and without stopping the treatment of organic waste water and the treatment of sludge such as the first sedimentation basin. Moreover, by disposing a sedimentation tank downstream of the phosphorus treatment tank, it is possible to remove as much phosphorus as possible from the organic waste water and reuse the adsorbent as a fertilizer.

(Example 10)
In FIG. 7, the figure showing the structure of the waste water treatment system which concerns on 7th Embodiment is shown.

  As shown in the drawing, the waste water treatment system 107 according to the seventh embodiment is configured such that a part of the treated water from the sulfur denitrification tank 32 and the aerobic treatment tank 8 is disposed between the anaerobic treatment tank 3 and the aerobic treatment tank 8. Except for further including a line 35 that returns to the sulfur denitrification tank 32 and a circulation device 34 provided in the line 35, the configuration is the same as in FIG.

  In the anaerobic treatment tank 3, organic substances in the wastewater are decomposed by anaerobic microorganisms such as methane fermentation bacteria and sulfate-reducing bacteria, and at the same time, biogases such as methane gas and hydrogen sulfide gas are generated. These biogas are sent to the hydrogen sulfide removing device 5 through the line 4, and after the hydrogen sulfide gas is removed, the biogas is discharged from the line 6 as a processing gas mainly composed of methane gas.

On the other hand, a part of the biogas dissolves into the anaerobic treatment tank 3 in the liquid phase, dissolved hydrogen sulfide gas HS as dissolved sulphide in the treated water ^- take or S ^2- forms.

In the sulfur denitrification treatment tank 32, the sulfur denitrification bacteria held in the treatment tank are subjected to anaerobic treatment of nitrate nitrogen in the aerobic treatment circulating water 35 circulated from the aerobic treatment tank 12 by the circulation device 34. It converts into nitrogen gas using the dissolved sulfide HS ⁻ from the tank 3. Nitrogen gas is discharged out of the system.

  In the aerobic treatment tank 8, when the sulfur denitrification treated water 33 is sprinkled from the sprinkling part 9 at the upper part of the aerobic treatment tank 8, aerobic microorganisms remove organic substances in the wastewater using oxygen dissolved in the liquid. Ammonia nitrogen is oxidized. Ammonia nitrogen is first oxidized to nitrite nitrogen and finally oxidized to nitrate nitrogen.

  According to the seventh embodiment, the anaerobic treatment tank 3 and the aerobic treatment tank 8 in the wastewater treatment method in which the anaerobic treatment tank 3 and the non-immersion type aerobic treatment tank 8 (watering type aerobic treatment tank) are combined. It is possible to remove nitrogen and phosphorus in the organic wastewater by combining nitrogen removal in the organic wastewater by arranging a sulfur denitrification tank in the middle.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the organic wastewater treatment system according to the present invention, the phosphorus-adsorbing substance used for removing phosphorus from the organic wastewater can be reused as fertilizer or a fertilizer raw material.

  DESCRIPTION OF SYMBOLS 2 ... Water supply apparatus, 3 ... Anaerobic processing tank, 5 ... Hydrogen sulfide removal apparatus, 8 ... Aerobic processing tank, 9 ... Sprinkling part, 10 ... Carrier part, 11 ... Sludge precipitation part, 13 ... Treated water storage tank, 14 ... Final treated water, 15 ... Phosphorus treatment tank, 101, 102, 103, 104, 105, 106, 107 ... Waste water treatment system

Claims (10)

An anaerobic treatment section for treating organic wastewater using anaerobic microorganisms,
A carrier part to which aerobic microorganisms are attached, and a watering part for sprinkling treated water from the anaerobic treatment part to the carrier part, wherein the treated water from the anaerobic treatment part is treated with the aerobic microorganism. And a first phosphorus adsorbent containing a calcium-based phosphorus adsorbing substance, and reacting phosphorus in the treated water from the aerobic processing section with the calcium-based phosphorus adsorbing substance to form hydroxyapatite crystals. A phosphorus removal wastewater treatment system comprising a first phosphorus treatment unit to be generated.   It is provided in the latter part of the 1st phosphorus treatment part, and further comprises a sedimentation tank which reserves treated water from the 1st phosphorus treatment part, and precipitates the hydroxyapatite crystal as a solid content. The phosphorus removal type waste water treatment system according to claim 1.   The first phosphorus adsorbent further includes a magnesium-based phosphorus adsorbing material, and the first phosphorus treatment unit uses treated water from the aerobic treatment unit as the calcium-based phosphorus adsorbing material and the magnesium-based phosphorus adsorbing material. And contacting with phosphorus in the treated water to produce hydroxyapatite crystals and reacting with phosphorus and ammonia in the treated water to produce magnesium ammonium phosphate crystals. Item 3. A phosphorus removal wastewater treatment system according to item 1 or 2.   The first settling tank provided in the preceding stage of the anaerobic treatment section, the line for sending the supernatant liquid from the first settling tank to the anaerobic treatment section, the sludge treatment section for anaerobically treating the sludge from the first settling tank, and calcium-based phosphorus A second phosphorus treatment unit that has a second adsorbent containing an adsorbent and reacts phosphorus in the treated water from the sludge treatment unit with a calcium-based phosphorus adsorbent to produce hydroxyapatite crystals; The phosphorus removal type waste water treatment system according to any one of claims 1 to 3, wherein   A first line for introducing treated water from the aerobic treatment unit into the first phosphorus treatment unit, a first pipe switching valve provided in the first line, and treated water from the aerobic treatment unit A second line for sending the water to the second phosphorus treatment section, a second pipe switching valve provided in the second line, and the treated water from the sludge treatment section is introduced into the second phosphorus treatment section A third line for switching, a third piping switching valve provided in the third line, a fourth line for introducing treated water from the sludge treatment unit to the first phosphorus treatment unit, and the fourth The phosphorus removal waste water treatment system according to claim 4, further comprising a fourth pipe switching valve provided in the line.   The second phosphorus adsorbent further includes a magnesium-based phosphorus adsorbent, and the second phosphorus treatment unit uses the treated water from the aerobic treatment unit as the calcium-based phosphorus adsorbent and the magnesium-based phosphorus adsorbent. In contact with the phosphorus in the treated water and the calcium-based phosphorus adsorbing substance to form hydroxyapatite crystals, and the phosphorus, ammonia and magnesium-based phosphorus adsorbing substance in the treated water are reacted to form phosphorus. The phosphorus-removed wastewater treatment system according to claim 4 or 5, wherein a crystal of magnesium ammonium oxide is generated.   The phosphorus removal wastewater treatment system according to any one of claims 1 to 6, further comprising a sulfur denitrification unit between the anaerobic treatment unit and the aerobic treatment unit. A process of introducing organic wastewater into the anaerobic treatment section and anaerobic treatment using anaerobic microorganisms,
Treated water from the anaerobic treatment part is introduced into an aerobic treatment part including a carrier part to which aerobic microorganisms are attached and a sprinkling part for sprinkling treated water from the anaerobic treatment part to the carrier part. Aerobic treatment using an aerobic microorganism, and treated water from the aerobic treatment part is introduced into a first phosphorus treatment part having a first phosphorus adsorbent containing a calcium-based phosphorus adsorbent, and the calcium system A phosphorus removal wastewater treatment process comprising a step of reacting a phosphorus adsorbing substance and phosphorus in treated water from the aerobic treatment section to produce hydroxyapatite crystals. An anaerobic treatment section for treating organic wastewater using anaerobic microorganisms,
A carrier part to which aerobic microorganisms are attached, and a watering part for sprinkling treated water from the anaerobic treatment part to the carrier part, wherein the treated water from the anaerobic treatment part is treated with the aerobic microorganism. And a first phosphorus treatment unit that has a calcium salt and reacts phosphorus in the treated water from the aerobic treatment unit with the calcium salt to produce hydroxyapatite crystals. Phosphorus removal type wastewater treatment system. A process of introducing organic wastewater into the anaerobic treatment section and anaerobic treatment using anaerobic microorganisms,
Treated water from the anaerobic treatment part is introduced into an aerobic treatment part including a carrier part to which aerobic microorganisms are attached and a sprinkling part for sprinkling treated water from the anaerobic treatment part to the carrier part. Aerobic treatment using aerobic microorganisms, and treated water from the aerobic treatment unit is introduced into a first phosphorus treatment unit having a calcium salt, and the treated water from the calcium salt and the aerobic treatment unit A phosphorus removal wastewater treatment process comprising a step of producing hydroxyapatite crystals by reacting with phosphorus.

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